Abstract: This invention relates to a semiconductor device comprising at least one p-n junction. The junction is formed from a "p" semiconductor contacting an "n" semiconductor. Said device characterized in that at least one of said "p" or "n" semiconductor is a nanoporous crystalline semiconducting material. These nanoporous materials have an intracrystalline nanopore system whose pores are crystallographically regular and have an average pore diameter of about 2.5 to about 30 .ANG.. Additionally, they have a band gap of greater than 0 to about 5 eV which band gap can be modified by removing a portion of the templating agent from the pore system of the materials. The materials which have these properties include, metal polychalcogenide compounds, metal sulfides and selenides, metal oxides, and metal oxysulfides. These materials can be used in a large variety of semiconducting devices such as light emitting diodes, bipolar transistors, etc. A process for preparing these nanoporous materials is also presented.